Everyone knows it–even, probably, those who continue to deny it: Climate change threatens the future of the planet. A few simple facts tell the story. Even 125,000 years ago, during the last period of significant global warming, atmospheric concentrations of carbon dioxide (CO2) were not as high as they are today. Yet sea levels were much higher, about thirteen to nineteen feet above today’s levels. Much of what is now New York, London and Shanghai was under water. The Intergovernmental Panel on Climate Change–a collection of more than 2,000 climate scientists and government representatives from around the world–has declared with virtual certainty that global warming caused by fossil fuel-based industrialization is upon us. Even if the world economy collapsed tomorrow and all CO2 emissions suddenly stopped, the earth would see several more decades of global warming because of the amount of CO2 already released. The challenge now is to stop runaway global warming: the process by which the effects of climate change “feed back” to compound the original problem in a vicious cycle that culminates in radically rising sea levels, mass drought, aquatic extinctions and social breakdown as the major cities of the world are overwhelmed by water, refugees and violence.

Because the scientific debate about global warming has been settled, this issue of The Nation focuses on how we should respond. How do we mitigate the crisis–i.e., make the rapid and radical shift away from fossil fuels so as to avoid runaway climate change? At the same time, how do we adapt to the changes in our climate that are already inevitable? The point is to grapple with the political economy of mitigation and adaptation–processes that pose distinct yet interrelated political and economic challenges. Consider, for example, the “climate divide”: The rich countries are disproportionately responsible for causing global warming, but it is the poor countries of the world that will suffer the most from the changes in store. This inequity has given rise to calls for climate reparations, in which wealthy nations subsidize the process of adaptation in places facing imminent peril, like Bangladesh.

At the same time, developed countries like the United States bear a special responsibility for mitigating the climate crisis. Americans are 4 percent of the world’s population, but we release 25 percent of all greenhouse gases. If we see the upper limit of atmospheric carbon stabilization at 400 to 450 parts per million, at which level the mean atmospheric temperature would be 3.6 Fahrenheit degrees higher than now, the heavy polluters of the world–the United States, the European Union, Japan and now China and India–need to reduce emissions by as much as 80 percent. That will require a massive effort. The Kyoto Protocol, widely viewed as inadequate, expires in 2012 and must be replaced by a far more stringent successor agreement. For its part, Europe has tightened its carbon reduction targets to 20 percent by 2020. In the United States, legislative proposals by Henry Waxman in the House and Bernie Sanders and Barbara Boxer in the Senate set the necessarily ambitious goal: 80 percent reduction in carbon emissions from their 1990 levels by 2050. To meet such targets, we’ll have to discourage emissions by putting a price on polluting gases like methane and carbon. The best way to do that is through taxation, which would be offset by tax breaks to soften the impact on poor and middle-class households and to encourage green job growth and investment. But such ideas face formidable resistance from a political establishment beholden to entrenched interests–the oil and coal industries–that stand to lose out. Those industries have sunk billions of dollars in investments that would depreciate in value if real carbon reduction targets were achieved. Thus, they fight tooth and nail with lies and canards to keep things as they are.

Lest despair take hold, consider that we are reaching a political tipping point; wide swaths of the global public are finally focusing on climate change. The momentum should increase as more and more people see the opportunities in the transition to a green economy. The capital markets of the world are clogged with money looking for profitable outlets. Surplus capital bids up asset value in one bubble after another: dot coms, stocks, real estate. And now, gluttonous military spending mops up more capital and gives it profitable expression as military Keynesianism on a vast scale. The United States hemorrhages $8 billion a month on the lost cause of the Iraq War. A crash course of mitigation and postcarbon transformation would harness huge amounts of surplus capital, employ millions of people, stimulate consumption, generate tax revenue and raise living standards while returning reasonable profits to firms building solutions to the problem of climate change.

Among those working on the link between job creation and clean energy is the Apollo Alliance–a coalition of labor, environmental, civil rights, urban, farm and business groups. Their plan includes: promoting renewables; upgrading existing energy infrastructure; improving efficiency in transportation, industry and buildings; research in new clean technology; and smart growth for metropolitan areas. Apollo estimates that $300 billion spent on its plan would generate 3 million new jobs and $1 trillion in additional GDP over its ten-year development. Call it the Green Deal: an environmentally based New Deal approach to crisis. Or call it whatever you want–the outline makes sense. In fact, these ideas have been percolating for years but have only recently begun to gain traction, as climate shifts have become unmistakable, with massive storms like Hurricane Katrina as well as the most recent nor’easter. Step It Up 2007, the nationwide mobilization in mid-April, kept the pressure on from below. But the scale and urgency of the crisis are such that the push for change must come from on high as well. In that regard the Supreme Court’s recent rebuke of President Bush’s EPA for failing to regulate greenhouse gas emissions was significant. While we can no longer prevent global warming, we can survive it. The knowledge is there; so is the capacity. What we need–now, while there’s still time–is the collective will to act.